redbird555

iTrader: (14)

Hi all, I'm putting together a stock ls6 longblock and I cant seem to locate a set of 243 heads with the sodium valves for a reasonable amount of cash. Question is do they really make any difference in power one would notice or that would be substantial? I know 01 ls6 motor didnt have the sodium valves and were rated at 385 instead of 405hp however it also had a significantly smaller cam which is what I attributed the 20hp gain to however someone today told me it was the valves that made up most of that hp. Originally I wasnt concerned with having those valves or standard ones on the heads but is it something i should be? I cant see those lightweight valves good for more than like 3hp, I thought it was mostly for valvetrain stability in sustained high rpms..
Thanks Dan

jthunderz28

good question I was wondering the same thing.

intenseblue

iTrader: (1)

3hp is probably about right due to reduction of reciprocating weight. The majority came from the camshaft, they had a descreened MAF and a larger air intake opening, and 2 cats instead of four

redbird555

iTrader: (14)

Interesting I didn't know about the cats and Maf I thought the motors were dynoed without a dull exhaust. A guy who was trying to sell me a set of the ls6 heads said they were worth 15hp which I figured was bs. No way lighter valves could reduce rotating weight that much

intenseblue

iTrader: (1)

LS6 have larger intake ports, completely different exhaust ports, and a far superior combustion chamber that is 2cc smaller. They would be worth 15-20 horsepower. And the 2001 Z06 had two cats on either bank back-to-back. In 2002 the smaller front ones on either side were deleted

Anthony Williams

iTrader: (3)

Sodium filled valves run cooler in high stress stituations, remember the LS6 was conceived to be a road race motor so this is the main reason GM put sodium filled valves in the LS6.

redbird555

iTrader: (14)

Oh i know that the heads arer much better than the ls1's hence why im using them however the valves are simply not worth that much power maybe a couple ponies on a good day. they were mainly used for longevity from what ive read.

usmonaro

Better valvetrain control & life. I doubt they would even affect hp any. I am putting a set of them on my GTO (LS1) right now. As stated the 20hp difference was cam/cats/maf.

SOMbitch

iTrader: (8)

The gain of a LS6 over a LS1 head is better flowing ports and a more efficient combustion chamber.

The lighter valves are easier to control allowing more rpm with less spring pressure. The intake valves are hollow and the exhaust valves are sodium filled to withstand the heat.

I am not sure where the line is when the extra strength of a solid valve is needed but I am sure at some point a solid is necessary..... it may be a solid roller motor I am just not sure....

Whiteaw57

iTrader: (2)

agreed with SOMbitch. Theres a point where a solid valve is needed, mainly with very high spring pressures. As for the lightweight valves remember too the 405 hp ls6 has a bigger cam and a 500 rpm higher redline than the ls1. I think it was more for a long lasting street car with a high rpm redline and the potential for a race motor more than anything. Are they worth it on a mild to moderate street car? absolutely! why not? Higher rpm, stable valve train, longer lasting valve springs, etc.

intenseblue

iTrader: (1)

and reduced reciprocating weight is worth power, albiet little

redbird555

iTrader: (14)

ya if the heads were even remotely close in price i'd go ahead and do it to have a built to spec ls6 motor but the fact is that the valves dont do anything for hp really and for a set of head with them everyone wants 600-700 for em whereas ive found regular 243's or 799s for 350-450 shipped to my house 3hp for 300 bucks isnt worth it imo. sure the stability is nice but many engines such as the ls2 do it with solid valves if anything ill get a good set of springs to help out. i also just found out thatt the valves weigh .86 lbs less as a set than standard ones so honestly i cant see that doing much i think you save more rotational weight with an underdrive pulley (abt 4lbs) that also slows the accessories to make power and it only gets about 7rwhp ...

Whiteaw57

iTrader: (2)

sure reduced reciprocating weight is worth a few horses but its not something youd readily see on the dyno. Maybe its worth a hundredth of a mile per hour at the track lol. youd get a bigger swing hp wise with the old lay a bag of ice on the intake trick (really doesnt do much)

O2Form

You all realize the ONLY reason to use a sodium filled valve is for the cooling effect it has on the seat? The sodium inside the valve melts at operating temps and ciculates moving the heat from the valve face to the stem. IT WON"T MAKE YOUR CAR ANY FASTER, but it will make it more realiable IF you road race.......................

redbird555

iTrader: (14)

one more question for you guys i asked a couple sonsors but either havent gotten replies or i was still a little confused. If i get a set of head soff of an ls2 car or trailblazer to my understanding it should have the ls6 valve springs not saying i wont upgrade but just in case... now some ls2 springs on gto's or trailblazers are the regular steel color with a blue or red stripe on them and they are the stock springs unlike the yellow ls6 springs are these the same specs as the yellow ls6 springs or are they weaker

02Z28ZO6

iTrader: (2)

The valves are lighter and therefore more reliable RPM's can be achieved as well as a few HP's. The suggested red line on an LS6 is 6800rpms where a stock LS1 is only 6200. I dont know if the valves are the only thing that allows the extra RPM range. I had also read that the older model LS6's had a much weaker casting, GM actually blew the back of the engines off during testing so the block casting was improved to allow crank case pressure to vent at high RPM's..

redbird555

iTrader: (14)

Its def not the valves while they help sustain high rpms people spin cammed ls1's to 6800 all day long. To rev high the ls6 and other engines used stiffer springs and cams with a broader power bond the ls1 stock simply doesnt have those components. Reason i asked the question above is that im looking at a set of stock 243 heads off an ls2 vette and the spring on it are a steel color are the still the same as yellow ls6 springs

dodson55

iTrader: (18)

it would be a very small hp gain if any

A.R. Shale Targa

iTrader: (2)

The lighter valves themselves are not worth a lot of horsepower but whenever
you can reduce parasitic frictional losses it means you can rev an air pump
to a higher rpm b-4 valve float and the engine will be making more power
@ the rpm it sees after each shift point also making the car faster !!!!!!!!!!!!

redbird555

iTrader: (14)

bumping this up guys. just had a friend bring upp this point and im not sure abt the answer. being the ls6 has a .550 lift and i wont be using the lighter valves will i need stiffer springs since the lighter valves helped with valve float? Ive seen people using the ls6 cam and springs on stock ls1 motor but just wanna make sure its ok some people have been saying it puts too much stress on the springs and the only reason ls2/ls3s get away with it is because they have lower lift cams.